Question

Completely factor the expression
245x^3 – 420x^2y + 180xy^2

Answer 1

245x^3 – 420x^2y + 180xy^2
=5x(49x^2 - 84xy + 36y^2)
=5x[(7x)^2 -2(7x)(6y) + (6y)^2]

we know the formula, (a-b)^2= a^2-2ab+b^2
comparing (7x)^2 -2(7x)(6y) + (6y)^2 with above formula , we get (7x - 6y)2

putting this in our equation, we get
5x(7x-6y)^2